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64 Cards in this Set
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Activated complex |
A stage reached in a reaction where n intermediate product is formed |
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Ea |
Activation energy |
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Activation energy |
The min amount of kinetic energy needed by reactants in order for a reaction to occur |
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Atom economy |
Compares the proportion of reactants that end up as useful product to the number that are wasted |
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Atom economy equation |
Atom economy(%) = mass of desired product __________________________ x 100 Total mass of reactants |
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Bond enthalpy |
The energy required to break one mole of bonds between the atoms in a mole of gaseous diatonic molecules, at standard temp and pressure (25°C and 1 atmosphere) |
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Bonding continuum |
A scale with ionic bonding at one end and pure covalent at the other with polar covalent in between |
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Ionic bonding |
Bonding that occurs between a metal and a non-metal element that have a large different in electronegativity |
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Carbonyl group |
O || C / \ |
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Chromatography |
A technique used to separate, identify and obtain individual substances from mixtures |
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Collision geometry |
The angle at which molecules collide |
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Collision theory |
States that for reactants to form products they must first collide |
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Covalent network |
A large 3D structure in which all of the atoms are covalently bonded to each other |
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Covalent radius |
Half the distance between the nuclei of two atoms, joined by a single covalent bond |
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Denature |
Breaking of hydrogen bonds in protein resulting in loss of shape of the molecules |
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Dynamic equilibrium |
The point in a reversible reaction where the rate of the forwards equals the rate of the reverse reaction |
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Electronegativity |
The attraction an atom in a bond has for the electrons of the bond |
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Energy distribution diagram |
A graph of the number of molecules against kinetic energy. Shows how the energy of reactants varies at a particular temp |
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Enthalpy change |
Change in energy which accompanies a chemical reaction |
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Enzyme |
A biological catalyst (made of proteins) |
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Free radicals |
Reactive particles which have unpaired electrons |
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Fullerene |
A molecular form of carbon |
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Green chemistry |
The design of chemical products and processes that reduce or eliminate the use of hazardous substances |
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Hydrogen bond |
When Hydrogen is bonded to: -oxygen -nitrogen -fluorine Resulting in a very strong PD-PD attraction between molecules |
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Hydrolysis |
The breaking down of a compound which involves the addition of the elements in watet |
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Hydrophobic |
Water hating |
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Hydrophilic |
Water loving |
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Ionisation energy |
The energy required to remove an electron from every atom in a mole of atoms in the gaseous state |
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Intermolecular forces |
Attractions between molecules |
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Intramolecular forces |
Attractions between atoms within a molecule |
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London dispersion forces |
Forces of attraction caused by temporary dipoles in neighbouring atoms or molecules |
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Mean bond enthalpy |
The average bond energy, taking into account the environment of the atoms forming the bond |
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Miscibility |
The ability of liquids to mix in all proportions, forming a solution |
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Molar volume (Vm) |
The volume occupied by one mole of a gas when measured at a given temp and pressure |
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Monatomic |
A substance that exists as individual non - bonded atoms (the noble gases) |
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Oxidising agent |
Accepts electrons from a reactant and so oxidises it |
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Percentage yield |
Compares the expected product quantity with the actual amount produced |
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Percentage yield eqn |
Percentage yield = Actual yield ----------------------- x 100 Theoretical yield |
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Permanent dipole - permanent dipole |
Forces of attraction occurring between molecules with permanent dipoles |
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Polar covalent |
The bond formed when two atoms share electrons unequally resulting in permanent dipoles |
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Pure covalent |
The bond formed when two atoms share bonding electrons equally |
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Rf value |
In chromatography, the distance travelled by the components of a mixture compared to the distance travelled by the solvent |
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Rf eqn |
Rf = distance travelled by compound --------------------------------------------- distance travelled by solvent |
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Reducing agent |
Supplies electrons to a reactant in order to reduce it |
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Reversible reaction |
A reaction which can take place in both directions |
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Solvent front |
The distance travelled by the solvent in chromatography |
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Standard enthalpy of combustion |
The enthalpy of combustion is the energy released when one mole of a substance burns completely in excess oxygen |
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Standard enthalpy of formation |
The enthalpy change when one mole of a compound is formed from its elements in their standard states and under standard conditions (25°C and 1 atmosphere) |
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Van der Waals forces |
The 3 types of intermolecular forces: -LDF's -PD-PD interactions -Hydrogen bonding |
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Enthalpy of combustion Eqn |
Eh = cm/\T Eh = enthalpy (kJ mol^-1) c = specific heat capacity of water (4.18 kJ kg ^-1 °C^-1) m = mass of water heated (kg) /\T = change in temp (°C) |
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Average rate eqn |
change in outcome Avg. rate = ----------------------------- change in time |
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For an endothermic reaction, is the enthalpy value positive or negative? |
Positive
(endo = no, not negative) (think ennnndo) |
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For an exothermic reaction, is the enthalpy value positive or negative? |
Negative |
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How does a catalyst affect the energy pathway of the chemical reaction? |
Lowers the activation energy (enthalpy change is unaffected) |
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How is a reversible reaction shown |
With a double-headed arrow |
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How will a temperature affect the kinetic energy of particles? |
Increasing the temp gives more particles kinetic energy >/= the Ea and vice versa |
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Which of the first 20 elements are monatomic elements? |
-helium (He) -neon (Ne) -argon (Ar) |
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Which of the first 20 elements are covalent molecule? |
-Hydrogen (H) -Carbon (C) -Nitrogen (N) -Oxygen (O) -Fluorine (F) -Phosphorus (P) -Sulphur (S) -Chlorine (Cl)
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Which of the first 20 elements are covalent network? |
-Boron (B) -Carbon (C) -Silicon (Si) |
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Which of the first 20 elements are metallic lattise? |
-Lithium (Li) -Berylium (Be) -Sodium (Na) -Magnesium (Mg) -Potassium (K) -Calcium (Ca) -Aluminium (Al) |
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What is Electronegativity? |
A measure of attraction an atom holds for electrons in a bond |
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Which is the strongest of the Van der Waals forces? |
1. Hydrogen bond 2. Pd-Pd 3. LDF's |
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Covalent bonds |
Occur between 2 non-metal atoms |
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Ionic character |
The difference in electronegativity of atoms in a bond. The greater the difference in EN, the greater the ionic character. |
